Why… Anything? With Harry Cliff
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January 21, 2025
TLDR: Neil deGrasse Tyson & Chuck Nice discuss quantum origins of the universe, charge parity violation, dark matter, and quarks with CERN particle physicist Harry Cliff.

In the latest episode of StarTalk, host Neil deGrasse Tyson and comedian Chuck Nice delve deep into the mysteries of the universe alongside particle physicist Harry Cliff from CERN. They tackle fundamental questions regarding matter, antimatter, quantum origins, and the enigmatic forces that shape our reality. Here’s a concise summary of the core topics discussed, providing valuable insights for science enthusiasts and curious minds alike.
Key Concepts in Particle Physics
The Matter-Antimatter Mystery
- Fundamental Asymmetry: The universe reflects a puzzling disparity—more matter exists than antimatter. This episode explores potential processes that could account for this imbalance, including CP violation (Charge Parity Symmetry).
- CP Violation: Harry explains that CP violation plays a crucial role in how particles decay and behave, potentially explaining why we observe more matter in the universe today.
Quarks and Their Characteristics
- The Quark Family: Cliff describes the six known quarks: up, down, charm, strange, top, and bottom (or beauty). Understanding these particles provides insight into the building blocks of matter.
- Properties of Quarks: Each quark is fundamental to the structure of matter, yet only specific combinations yield protons and neutrons, which form atomic nuclei.
Insights from the Large Hadron Collider (LHC)
Function and Purpose
- LHC's Role: The LHC is a particle accelerator that serves to recreate the conditions of the early universe. Cliff works on experiments involving B mesons, searching for anomalies that could break current theories of particle physics.
- Data Analysis: Cliff and his team analyze vast amounts of data to identify unusual particle behaviors, which could point to new physics beyond the Standard Model.
Anomalies and Discoveries
- Space Audities: Cliff’s latest book, "Space Audities," focuses on unexplained phenomena that challenge our current understanding of physics, stimulating curiosity about the unknown aspects of the universe.
- Electroweak Symmetry Breaking: The episode discusses how this phenomenon, which occurred shortly after the Big Bang, may have contributed to the distribution of matter and antimatter.
Dark Matter and Dark Energy
Unsolved Mysteries
- Nature of Dark Matter: Although dark matter is known to exist due to its gravitational effects, its composition remains a mystery. Researchers continue to seek direct evidence through various experiments at the LHC and specialized underground facilities.
- Dark Energy Challenge: While dark energy drives the universe's accelerated expansion, its understanding eludes physicists. Theoretical discussions propose quantum fluctuations as potential explanations, though current models still face significant discrepancies.
Particle Lifespans and Decay
- Short-lived Particles: Many particles, such as neutrons, have extremely short lifespans, decaying in mere moments. Understanding these lifespans is crucial for studying particle interactions and behaviors in high-energy environments.
- The Conservation Laws: The discussion highlights the role of conservation laws in particle decay, including how certain particles can transform and the conditions under which they do so.
Practical Applications and Theoretical Implications
The Impact of Scientific Inquiry
- The Nature of Discovery: Cliff emphasizes the importance of exploring the unknown, suggesting that breakthroughs often arise from investigating anomalies or discrepancies in expected results.
- Future of Particle Physics: The dialogue explores possibilities for future discoveries, encouraging continued exploration of theories such as quantum gravity, which seeks to unify quantum mechanics and general relativity.
Conclusion
This engaging episode of StarTalk sheds light on the complexities of particle physics and the fundamental questions that remain unanswered about our universe. With Harry Cliff’s expertise and insights, listeners gain a deeper appreciation for the ongoing quest to uncover the mysteries of matter, antimatter, and the very fabric of existence. As we continue to explore these cosmic queries, the dialogue encourages an appreciation for both the known and the unknown in the realm of science.
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So love me some particle physics. Who doesn't? Foundational. Yes. In the world. Yes. And I foresee a day where you walk into your kitchen and they're all just the particles of the universe. And you just put whatever you need and make whatever you want. That's cool. And I foresee a day where we will end this matter, anti-matter feud.
in the octagon coming up. All you ever thought you'd care about in the realm of particle physics on Star Talk. Welcome to Star Talk. Your place in the universe where science and pop culture collide. Star Talk begins right now.
This is Star Talk. You have the grass ticing here. You're a personal Ashgrove physicist. Chuck, nice there. Hey, man. What's happening? Can I say you're their personal comedian? No. Okay. Do not involve yourself with me on a personal basis at all. Okay. Okay. Take it back. Take it back. Today is going to be a cosmic queries. Yeah. Yeah. But not after we learned some stuff. Yeah. Yeah. And it's good stuff. It's good stuff. Yeah. All right. It's going to be a particle physics. Wow.
I didn't know it was going to be that good. You know, I know a little bit about particle physics, but I'm not an expert. Okay. So anytime we hit this kind of impasse, we've got to bring in the expert. Right on. And where's sort of best particle physics in the world happening? The collider. The collider.
That's a start, okay. Yeah, it'll be a collider. We've got someone who's worked at CERN in Geneva. And he's a particle physicist at the University of Cambridge in the UK. Oh, dear. Help me welcome Harry Cliff. Harry, welcome to start talk. Harry.
Great to talk to you. Thanks for having me. Yeah, so you worked with the Large Hadron Collider, which is one of the experiments of CERN. And what did you do? What was your role with that?
Well I still work on it actually so the LHC is this massive 19 mile ring buried underground and there are actually four experiments on the ring so these four places where we smash particles together and I work on one of them which is called LHCB and the B stands for beauty which is a type of particle that we're interested in studying.
So I still work there, I analyze data, look for places where our current theory might break down, or that we haven't found in the yet, which is a bit frustrating. Although we're getting some hints, but that's the general job. It's going through loads and loads of data, trying to find places where we're seeing new effects we've not seen before.
But beauty, that's not one of the names on one of the quarks, is it? It is, yeah. So there are these six quarks that make up, well, two of them make up the nucleus of the atom, and then there are four others, and they have weird names. So the first two that were found after the original two were called Strange and Charm. And then the last two, there was this disagreement about what to call them.
Some people wanted to call them truth and beauty, which is really lovely and poetic. But in the end, most physicists call them top and bottom, which is a little bit boring. But because we work on these particles, we study these B quarks. We rather be known as beauty physicists and bottom physicists, so for us at least, it's beauty. It's got my vote. Yeah, beauty? Yeah. Truth and beauty. I got to say, though, I just think top and bottom might be a bit more interesting in some respects.
It's a family show. Harry, you left off the up and down quark, so completing the family of six quarks. So get up and down, up and down. Yeah, that's right. Strange and charmed. Yeah. Truth and beauty. Top and bottom. That's it. Top and bottom. Exactly. That's right. That's right. Six. As far as we know, maybe there's more, but we've only found six.
Okay, so you're a quark man. We got to love the quark people. And I'm delighted just because I reached the public often that you've written two popular level books. I love it. And I'm looking at the title of your first one, how to make an apple pie from scratch in search for the recipe of our universe. Oh, wow. Well, that evokes something Carl Sagan said. It's 1980 cosmos. Okay. They said, how do you make an apple pie? You just start with a big bang.
Did that inspire this title? Yeah, absolutely. Yeah, that scene. I think it's episode five where he's sitting in, he's actually sitting in Cambridge in Trinity College and this apple pie is brought out to him. And he looks at the camera with a little twinkle in his eye and says, if you wish to make an apple pie from scratch, you must first invent the universe. And then he kind of goes off to talk about how the atoms in the apple pie were made inside stars. So it's kind of like, it's quite a well known phrase in physics. I came up
like during my university education. So it was kind of, I thought it was a neat way of talking about, you know, what the universe is made from, but through the lens of trying to find out how you make an apple pie, but a really complicated recipe. Let's just get down to basics. Yeah, I was going to say, I'm going to be honest though, it's a long walk around the block to get to an apple pie. Good things take a while, you know. But it's cool. It works. It's 14.8 billion years.
But I'm specially delighted by your recently published book. I love this title, Space Audities. That's very David Bowie of use. Space Audities. In fact, that was his first hit. Did you know this? David Bowie's first hit was Space Audity. Oh, okay. Okay. Okay. Round control to Major Tom.
That's what put them on the map. That's the title. The subtitle is the mysterious anomalies challenging our understanding of the universe. Ooh. Ooh. Interesting. It's based on that that we solicited questions from our audience, from our Patreon supporters. We'll get to those in a minute. Right. And I want to first extract more physics out of you. Tell us more about our inventory of fundamental particles. Are we there yet?
If we're there, I'll be out of a job. So I really hope there's more. We know about 17 particles in total at the moment. So there are the six quarks that we've already talked about, two of which make up the nucleus of the atom. Then there's the electron, which goes around the atom. And the electron also comes in this triplet. There are three electron-like particles. The next one's called the muon, and then something called a tau.
So that's another three that gets you to nine. And then there are three neutrinos, these like ghostly particles that zip through the universe and through us. And we don't really notice most of the time. So that gives you 12, what we call matter particles in total. The neutrinos are related to the three species of electrons, right? So they're kind of, can we think of them as a family?
Yeah, exactly. So the electron has a partner called the electron neutrino, the mu one has its own version neutrino and the same for the towel. So yeah, you got these 12 particles. I mean, that in itself is a mystery because they come in these like three copies, these what we call the generations, and we don't know why. It's very mysterious. So it's kind of like we have these Lego bricks in our set, but we don't understand why we have these particular pieces.
And then there are the forces. So there are three forces in our quantum description of the world. We don't include gravity. We don't know how to deal with that yet. But we've got the electromagnetic force, the weak force, and the strong force. And they each have particles. So the photon is the particle of light that goes with electromagnetism. Then we call it gluon, which is the particle of the strong force that sticks the quarks together. And then the W and Z bosons, which are the particles of the weak force, which is this
weird force related to radioactive processes and other things. 16 in total. And then the last one, which was found about a decade ago at the LHC, which is the Higgs boson. So that kind of finishes off our 17 particles and what we call the standard model. But we don't think that's the end of the story for lots of reasons. Mostly to do with astronomy, actually, thanks to you and your colleagues discovering this inconvenient stuff out there in the universe called dark matter. So that suggests there must be more stuff that we haven't found yet.
Interesting. Yeah, whatever dark matter is, we have no idea. And maybe these guys will find it in their particle accelerator. Right. And if they do, we'd be very happy. Because right now, it's just this term in our equations. Right. It's like... But we know it's something. Something's there. Something's there. So we throw it in the equation. Right. And let somebody else figure out what the hell it is. What does something there? What about dark energy, though? Because...
That's not a particle. Well, we don't know. Harry, Harry, Harry, I'm going to throw this one over to you, Harry. I mean, yeah, no, we have no idea, right? We have absolutely no idea. I think it's fair to say. I mean, this is when particle physicists try to talk about dark energy, things go really badly wrong. So I should be careful. But there was this original, well, the idea, one idea for what dark energy is, is
What we call vacuum energy, so it's the energy left over an empty space once you've taken away everything else, all the atoms and all the particles. In particle physics, the actual truth is that particles aren't really the fundamental ingredients of the universe. They are actually made of something more fundamental, which is called a quantum field.
So for all of these 17 particles we've talked about, there is a corresponding field and the particles are actually like little vibrations in that field. They're like ripples in an ocean, if you like. So those fields, even when you've got rid of all the particles, they're still there in the vacuum. And if you take the idea was that maybe dark energy is all the kind of quantum fluctuations that's left over in these fields in the vacuum.
But if you run the numbers, you find you get an answer that is 10 to the power 120 times too big. So that's 10 with 120 zeros at the end, which is like a ludicrously enormous number. If it was that big, the universe would be ripped apart in an instant. So we have no idea what's going on really from a particle physics point of view. So it's the biggest discrepancy ever between a theory and an observation.
However, couldn't there also be something else since we don't know what that is? Couldn't there be something else that's tamping the field so that it isn't ripping? Now you're just making stuff up. That's just as feasible as a field. No, you're dead right. This is what theorists do. They go, okay, this number is crazy. So let's add in another thing that cancels us out. That's exactly what people try to do. So you could be a theoretical particle physicist.
This is just perhaps semantics, but of your 16 particles plus the Higgs boson and minus the three force carriers, so that takes us down to 13, I think. Do you count their antimatter
versions of those particles as separate particles? Yeah, I mean, you can multiply that number many times. So like the quarks, for example, the version of electric charge for the strong force is called color. And whereas with electric charges, only one type of electric charge in the strong force, there are three
They're called red, green, and blue. So you get red quarks, green quarks, and blue quarks, bizarrely. So that means actually there aren't six quarks that are 18. If you're adding the anti-quarks, that gives you 36. So you can go up to like crazy numbers if you take all these things into account. But basically the anti-particles.
They exist in the same field. So you have your electron field, an electron or an anti-electron are just different sorts of vibrations, but in the same fields. We tend to just count that as like one thing, not two. And if you, because you started doing that, it gets mad. Okay. I'm interested to clarify that. We were talking about the lifespan of particles before the show. And you mentioned that you measured a particle.
For his PhD thesis, measured particle and its lifespan was one trillionth of a second. And you said that that was relatively long? Yeah, I mean, there are only a couple of very privileged particles that live forever.
There is the electron that we think lives forever and the proton that lives forever. Everything else decays eventually, even like the neutron. If you have a neutron floating about in space, it will decay in about 15 minutes. So as you get heavier and heavier.
Particles tend to decay. Interesting. Yeah, 15 minutes. That's it. If you break off a neutron and set it free, 15 minutes later, it just goes. It turns into a proton and an anti-neutrino. You tell me, what are the decay products of a neutron? It turns into a proton, an electron and an anti-neutrino. You get three things out. Ah, got you. OK.
And here's something cool. I want to show off the little bit of particle physics I know. You hear what he said. Your neutron becomes a proton, an electron, and an anti-entrino. The kind of particle the neutron is, you can end up with something that isn't that kind of particle when you're done.
Okay, these conservation laws. It's okay for the neutron to become a proton, but wait a minute, the proton has a plus one charge. So now you gotta cancel that out. So we cancel that out. Wait, the proton has a, oh, wait, wait, the proton, so it's a proton plus one. Who's got a minus one? Electron. He said, so those cancel, we're good. However, we now have an electron that's a kind of particle that we didn't start with.
We gotta undo the fact that we now have an electron. Cuz you gotta need the conservation. You gotta concentrate it. And so how do you get rid of the fact that you now have an electron? And the electron is paired up with these neutrinos. And what do you say? You not only get the electron, you get the anti-neutrino canceling out the electron.
Now that's a great way to balance this out, but my question is, do these things, are these things actually here? Or are you just saying, okay, we need this to cancel it out? Well, take us there. Are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you, are you
Well, I mean, I guess it goes back to 1896. So, Henri Becquerel, French physicist, famously discovered radioactivity in his lab when he left these uranium salts on top of a piece of photographic paper. And he saw that even when there was like a bit of card in between the salt and the paper, the photographic
film got exposed. So that was what he was seeing there were prot... were neutrons decaying into protons, basically. That was the radiation that was being emitted by those uranium salts. So we kind of knew about this process. It was called beta decay back in those days. And then Ernest Rutherford and others studied it in the late 19th century. So we kind of knew about this process way before. We even knew what a neutron was. That took another 40 years or so. So the phenomena appeared first and took a lot longer to actually figure out what was going on.
The beta particle was the electron, correct? Yeah, exactly. That's right. Yeah. Because at the time, we didn't know about neutrons. Neutrons would come. We didn't know about neutrons until 1930. So we had to have clumsy other language to account for this. OK. Yeah. So you're saying that the universe is requiring it of us to recognize these properties. And they become rather helpful, correct, in calculations you do and predictions you make.
Yeah, I mean, this whole, the whole subject of particle physics, it's kind of built on this idea of mathematical symmetry, these symmetries that are either respected or broken. And that generates this very powerful mathematical description of the universe. And I mean, this way of looking in the world is extraordinarily successful, like to give you an example, how amazing this theory is.
There's one quantity that we can, one example of a quantity you can use to calculate is the magnetism of the electrons. The electron, as well as having an electric charge, it behaves like a little magnet and emits a magnetic field. And you can calculate how strong that little magnet should be to one part, I think now 10 billion.
And if you do an experiment, a really, really precise experiment, you get the same number to 10 decimal places, which is crazy. So this kind of way of looking at what is incredibly powerful. But at the same time, we know we're massively missing something because we don't know what dark matter is or dark energy or any other stuff. So it's this amazingly successful theory, but also incomplete.
Yeah, it's you know enough about the universe to quantify your ignorance. I'm going to say, yeah, without doubt. Anything you get to 10 places, you pretty much nailed it. Yeah, you nailed it. I'm Jasmine Wilson.
and I support StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson. Let's go to our questions now. By the way, they were our Patreon supporters. These are patrons of StarTalk. They are occasionally solicited for questions they might have.
specifically to him for the guest. So you're not in studio with us, you're coming to us from London, but that doesn't matter to the questioner, they don't care where you are. No. All right. What you got, Chuck? All right. He says, hi, start talk team, Andrew here from Quirk City, Ireland. Dr. Cliff, can you please explain how your research on CP violation in B mesons contributes to our understanding of the matter anti matter asymmetry in the universe. Thanks. I like that. Let me, let me tee this up.
Okay, because I can do the astronomy part of this. And then he can go in to the particle part of it, right? So you look in the early universe, you have matter and there's energy there. And matter and energy we know are equivalent. And from this bath of energy, you can spontaneously make particles. And if you do that, the laws of symmetry of the universe say the particles are matter, antimatter pairs. And it came out of nothing. You got to be able to come back together and be nothing.
Okay, so you got the, and this is just going on. Okay. And, but at some point, the universe out of this soup of energy created one extra medical particle for every hundred million particles that it made. And so in the dance off, all the pairs go away. So that's annihilation, annihilation, annihilation, annihilation. And it's one person left.
It's got nobody to annihilate with. That is everything we know and love in this universe that we call matter. So wait a minute. All matter. Yes. From that one. Wait. Yes. All matter. Yes. Yes. Everything else is a photon. Everything else turned into. From this left over just the one out of 100 million playing musical chairs. In musical chairs. Everybody pairs off. Right. And they're happy. Right. And then you think everybody's paired and then one person is left.
and there's no one to pair it with evermore. And that makes up everything. All the matter that we love and know in this universe. So Harry, why did you do this? I mean, I wish I could claim responsibility for this. This is to the universe. Well, I mean, yeah.
This is a big problem, as you say, because we see this in experiments. When we bang particles together at the Large Hadron Collider, you always see equal numbers of particles and antiparticles being made. So this is what happens. So the question is, how did you get this asymmetry? And there was a Russian physicist back in the 70s, I think, called Andrey Sakharov, who came up with three conditions that had to be satisfied to allow matter to win this battle with antimatter in the early universe.
The first one, pretty obviously, is you need a process that makes more particles than antiparticles. That's number one. The second one, though, is this condition known as CP violation. CP stands for charge parity, which is a sort of symmetry that relates matter to antimatter. It's kind of like a mirror. If you put matter in the CP mirror, it shows up as antimatter.
So what we're looking for are processes that violate this symmetry. And these B mesons that the questioner asked about. So these are particles which contain a beauty quark and another quark. So I paired up with an anti-quark usually. And there are particular type of these particles that do this really weird dance where you create one of these B mesons. And as it travels through your experiment, it oscillates backwards and forwards between matter and antimatter. So it will flip its identity with this very nice sort of periodic way.
And what you then do is you watch how often does it decay in the matter state, and how often does it decay in the antimatter state? And you measure the difference. And if you see a difference, that tells you that the laws of the universe violate this CP symmetry, this symmetry between matter and antimatter. So this is the kind of key ingredient, one of the key ingredients we need to explain this mystery.
The universe has the power to violate its own laws by this process. Yeah, exactly. So this was first discovered, I don't know, back in the 80s originally, and we're studying it in lots of different particles now. So we know that this CP symmetry is broken, which is a good thing, because if it wasn't, we wouldn't be here. But the mystery is
Our current part the particles we know about don't break it enough so the symmetries is very is very very slightly broken and we need way more of this symmetry breaking to explain the fact that we exist in the universe is there to look at. I didn't know we had any mechanism at all to break the symmetry I'm.
Cockles are warm, but it's not. Okay, next question. That is fascinating stuff. Okay, this is Saren Sarkar, friend of ours, is matter-antimatter asymmetry the cause for
four of the Big Bang, we just talked about it, but could that, I mean, are you going to make a Big Bang, man? Yeah, when you're hiding from it. Astrophysically, it happens much later than the formation of the universe, but with your Large Hadron Collider, you are probing the conditions
that would have prevailed at the Big Bang itself or very close to the very beginning. So do you think that this, I'm reading this question, that this matter, antimatter asymmetry would have mattered before it otherwise mattered astrophysically in the universe? I mean, it's not. We don't really know when the process that
broke the symmetry happened it could have had so the l h c as you say it's kind of recreating the conditions of the big bang with probing conditions that existed about a trillionth of a second after time zero if there was ever such a thing. So that's kind of where we are and that there is a possibility that that was the moment. It's all actually related to the Higgs boson there is this thing that happened about a trillionth of a second into the universe's existence called the called electroweak symmetry breaking.
which is basically where the higs field which gives mass to the particles that we're made from switched on for the first time and that reset the laws of world reset the basic ingredients of the universe set the form of the forces and it was a sort of a transition a bit like water boiling it's like a kind of like a change of state but a change of state of the vacuum itself.
And that may have been the moment which created more mass than antimatter and that's why we're doing one of the reasons we built the LHC is to recreate those conditions to see if we see that process happening. These phase transitions you said water boiling to going from just regular water to boiling or even freezing right water going it's water completely changing its state.
And you now use this vocabulary sort of loosely in the early universe, or maybe literally, the universe is changing its state of existence. Are you just saying, if it's going to happen anywhere, that's where it's going to happen? Because that's where there's some serious action going down the pipe.
Yeah, I mean, it's, well, theoretically you can, when you do the, you sort of figure out what this event looked like under certain conditions, you find in the equations of the standard model that you can make more particles than antiparticles in certain, this phase transition has to happen in a very particular way.
And you actually need more particles than exist in the standard model. So the standard model on its own can't do it, but the standard model plus some other things can do it. But it's also possible it happened earlier. So we're talking like, you know, not a trillionth of a second after the Big Bang, but a trillionth of a trillionth of a trillionth of a second. So you're getting closer to time zero. That helps me.
become more accepting of the fact that you can blame these transition. You can blame all the weird oddities that are going on on these transitional moments in the universe, right? Because that's where stuff is going down.
Excellent. Time for a couple more. What did what you got? All right. You know, I'm going to go to Magnus here. Says, Magnus, I am Magnus, son to a fallen father, husband to a murdered wife. I am Magnus, and I shall have my revenge. Okay, I'm sorry.
That just come out of you. It just sounds like what you should say. If your name is Mac, you know, clearly the plight of Mac. All right, he says, my respects, Dr. Cliff, may you describe the link as you see it between a quantum field theory as the gold standard of the standard model until now a perfect description of our current knowledge. B, various versions of quantum
gravity, i.e. strength theory and loop quantum gravity, which depend on the idea of CFT duality with or without background dependency. And just to add, I'm a Swede in Switzerland confusing. No?
All right. Okay. So it's only confusing to Americans, okay? Magnus, because... So what is that question? I don't get the question. Go ahead. So Harry, did you follow the question? I think so. I think they were asking about, well, the relationship between quantum field theory, which is the language of the standard model, the language of particle physics, and string theory and loop quantum gravity.
I think that was the question. I mean, what I would say is that I am really underqualified to talk about quantum gravity, not my area. I think the, but what I would say is that quantum gravity theories, they say very little about particle physics at the moment. So, you know, string theory, loop quantum gravity, whatever your favorite flavor of quantum gravity theory is,
It has no bearing on any experiments that we do in high-energy particle physics at the LHC. And one of the big problems with these theories is they don't really make testable predictions so far. So I would love it if string theorists or someone else could come along and say, if string theory's right, you can do this experiment at a collider and you'll see this. But so far, that hasn't happened. So really, quantum field theory is the kind of gold standard. It's the theory that works. Maybe it'll be replaced by one of these theories later, but I think we're away from that.
Interesting. All right. So what he says, he doesn't care about gravity. I'd love to include gravity. I'd love it, but it's a hard problem. Currently, what is our best understanding of the most things going on in the universe? Is it just sort of quantum field theory? Is that what gives us the best understanding of everything? And maybe we'll just have to modify that? Or is there something else ready to take over all of it?
waiting in the wings, an umbrella to it all. As you know, in modern physics, we have these two pillars which describe pretty much everything in physics, which are quantum field theory, on the one hand, which describes particles, quantum mechanics, all that stuff. And then we have gravity on the other hand, in general relativity, which is a classical theory, a non-quantum theory.
And so you have these two separate theories, but they actually don't really overlap with each other. I mean, the only places where you would see quantum gravitational effects are at the center of black holes, or at the very earliest moments of the big bang, these really extreme conditions. For everything else, these two separate theories work perfectly well. And that's kind of the problem, actually, because the only place you get evidence for quantum gravity are in these really extreme conditions, which we're way, way away from being able to recreate in the laboratory. So that's what makes it very difficult.
Cool, man. All right, give me another one. All right, here's another one. This is Friedrich Johansson, who says, hello. Friedrich here from Northern Sweden. I think. Friedrich from up in the hood. Right. Hello. Friedrich here from Detroit.
So he says, Friedrich here from Northern Sweden, do all fundamental particles of a type have exactly the same mass. And how can we know that? Oh, I love that. That's a really cool question. I love that. So are all.
particles of any species identical in every way to the limits of all measurements. I mean, well, because you can measure it, right? So, yeah, every electron is exactly the same as every other electron. Every proton is exactly the same as every other proton. And the reason is, well, protons are a bad example, actually, but say electrons. The electrons are actually made of this thing called the electron field, which is invisible fluid-like thing. It's all looked throughout the universe. And every electron is a little ripple in this same field.
As a result, when you hit the electron field, you make an electron, you make the same type of thing everywhere. That's why they're identical. You can always argue that every electron is the same thing. It's part of the same object. Every particle of a certain species is an absolute identical and indistinguishable. That's really fundamental, actually, to our understanding of particle physics and quantum theory. Is it a borg like that? Yeah, that is a borg. Every of the members of the borg, they're not invisible. Conscious wise.
They're all one entity. They're all one entity. Although electrons don't come along and try and turn you into an electron. All right. Go ahead and start your geek. I am low cutest of electrons. Resistance is futile.
But part of the question was, how do you know, because you haven't measured every electron in the universe, and you're saying, you know enough about the field to know that there's only one kind of particle it can make in that case, and therefore you're gonna get the electron every single time. That is really cool. Yeah, no, yeah, yeah. Oh man, okay.
This is Yazan al-Hajari, and he says, cheers from New Jersey. Okay, all right. I'm Yaz, an artist and filmmaker studying relativity. I'm fascinated by how Einstein's theory is applied to the Large Hadron Collider, where particles approach to the speed of light. Dr. Cliff, could you explain how relativity shapes our understanding of these high energy collisions, and whether it might someday be possible to safely create
A small black hole somewhere in the collider. And Neil, if that were possible, would you like to throw something into that black hole? Totally. Oh yeah. Okay. We can make it like an amusement park.
game. Hit the black hole and it just disappears into the singularity. That question reminds me of earlier in our conversation. So, Harry, you studied particles that decayed in a trillionth of a second. It seems to me that can be a trillionth of a second only at a certain speed.
because the faster a particle goes, the longer it would take to decay because its timeframe is shifted relative to the observer. So you can't just declare a 20th of a second without specifying a speed or is that particle at rest?
So that, that trillionth of a second is from the particles point of view. So in the frame of the particle, so the particles are rest basically. So if you were the particle, you'd live a trillionth of a second. But from our point of view in the lab, as you say, these things are going close to the speed of light. So they live way longer. So they actually will travel, they live long enough because of this relativistic time dilation to fly a centimeter or so in the experiment, which if they just live a trillionth of a second, they wouldn't go anywhere near that far. So you're absolutely right. I mean, like,
Relativity, special relativity, I should say, is fundamental to colliders, because what they basically do is they are E equals MC squared machines. They take E energy, kinetic energy in these accelerated particles, they bang them together and they make M, they make new particles, new matter effectively. So it's absolutely fundamental to what we're doing. But the question about black holes, that's really general relativity. And there were some ideas back when the LHC switched on that
If there were extra dimensions of space, so extra directions that you can move in, that it would be possible to create microscopic black holes at the LHC. And this led to a load of tabloid stories about the LHC is going to create a black hole. It's going to swallow Geneva and then swallow the rest of the planet and we're all going to disappear.
And so this calls such like a big storm in the British, the British tabloid press actually really got hold of the story. CERN had to create this health and safety report, which is the most exciting risk assessment you'll ever read. And it basically describes these various hazards, one of which is like a black hole that swallows the earth. The other is the creation of
a bubble universe that expands to destroy the entire reality so they had this risk assessment where the destruction of the universe was one of the possible outcomes and they basically said this is very unlikely to happen and so it's all fine. You still got money they gave you they still let you do it well no one's going to sue you if you destroy the planet right.
He's already thought this. There's a YouTube video before the Large Hadron Collider was turned on, but there's a countdown to it. There's a YouTube video of the parking lot outside of CERN, and you have the clock counting down, and then it gets to zero, and then the parking lot folds. On itself, wow.
It's pretty funny. I'm not terrifying. Yeah, I was going to say, it's funny if you're an astrophysicist. For the rest of us, it's not funny. I should say there is a reason why we knew this wasn't going to happen. And that's because the universe has been doing this experiment for billions of years where we have protons that hit the upper atmosphere much higher in energy than the LHC. So if this was possible, every object in the universe would have been turned into a black hole. So we kind of knew for that reason that it wasn't going to happen.
All right, there's no greater particle accelerator than the universe itself.
Look at that. All right, all right. This is Viper who says, hello, Dr. Tyson, Dr. Cliff, Lord, nice. I am Sam from O'Fallon, Missouri. I am 16 and have been wondering about tachions for a few years now. I would like to know more about them. And if you guys can go into more depth explaining what is the deal with tachions.
Wow. Okay. Yeah. I mean, well, all I really know about Tachyon's is they're hypothetical particles that travel faster than light, but I don't think they're allowed to exist because they would violate causality, this idea that like one event leads to another and not the other way around. So they are, I think there are things you can kind of cook up in your equations, but they're basically forbidden. They turn up in Star Trek, I think, or like, you know, science fiction as a way of like,
facilitating time travel, but all the time. But I don't think that there are things that can exist in reality, but maybe Neil may know more about this than me. Well, let's see what Merlin has to say about this. Yeah, Merlin. Mm-hmm. What is a tachyon? Rickman Farling, Dallas, Texas. Tachyon's are hypothetical particles that travel faster than the speed of light.
named for the Greek takis, meaning swift, where we also get the word tachometer. Einstein's equations of special relativity bestow this particle with an array of bizarre properties. Here are the top five. One, the slowest tachion can move is slightly greater than the speed of light. Two, a tachion can have infinite velocity.
When a tachyon loses energy, it speeds up. When it gains energy, it slows down. A tachyon appears to travel backwards in time for some observers. If you send your friends a message with a tachyon, they can receive the message before you send it.
Tackyons have yet to be detected. There you go. And there's the end. That'd be useful for those emails that you forget to reply to, right, that sit in your inbox for weeks. And then if you could send them back in time, that would be amazing. Yeah, and my favorite Tackyon account would be you see someone walking down the corridor.
and then they slip on a banana peel. But he's your friend, then you don't want them to be harmed. So you go to a tacky on texting app, okay? And you, cause it's already happened. So you send them a text and say, watch out for the banana peel. So then they get the text before they step on the banana peel. So now the person's walking down the corridor and they get a text. And they look at the text and it says, watch out for that. And they slip on the banana peel.
Because of your attacks. Because of your attacks. All right. There it is. Chuck, we got time for one. Maybe two more questions. Actually, let's go with Jonas Draveland. And Jonas says, good morning, Dr. Cliff, Dr. Tyson, and Astro-Lord Nice. Okay. Jonas from the Appalachian foothills of North Carolina here. Is there any dark matter in my living room? Oh.
or stated more seriously, is dark matter scattered throughout the universe, or is it all in clumps around distant galaxy clusters? If it is present on Earth, does that allow one to search for it in settings such as your collider, sir? Oh, I love it. Well, thank you, Jonas. What a great question. Even when you live in the hills of the apple, you got a lot of time on your hands. Yeah, he's taking hikes and thinking about dark matter. Yeah, so what you got there?
I mean there's definitely there would be dark matter in your living room yeah for sure because we while this is actually really astronomy rather than particle physics but the idea is that every galaxy like our own sits in this big spherical cloud of dark matter and the galaxies kind of in the middle of this cloud so if there are dark matter particles floating around in the galaxy they're floating through us and through the earth and then there'll be a few in the room.
It depends on how massive they are as to how many they would actually be, but yeah, they'd be there. And that doesn't actually help us at the LHC, because at the LHC we're trying to make them out of energy. But there are other experiments that go live down big mineshafts where you have tanks of really cold, xenon, or other kinds of noble gases, and you wait for a dark matter particle to drift,
through the earth, hit a xenon atom in your detector and create a little flicker of light and then you directly detect dark matter. So it's a bit like a poltergeist moving, throwing some crockery around in your living room. That's kind of what we're waiting to see. But they're these detecting more and more and more sensitive. They still haven't seen anything, which is very frustrating. But hopefully one day they'll pick something up.
Last question. All right, this is David Smith. He says, hello, Dr. T, Dr. C, Lord, nice. Dave Smith here, hailing from Naples, Florida. How do you know you have found antimatter if antimatter and matter cancel each other out? Is it the violence of the interaction, the aftermath, or the moment of ever so slight when you see the matter and antimatter just before their epic
confrontation. So he made it into a boxing match. Like he, yeah, he's the Don King of Particles. Particles in the octagon. Exactly. Two particles enter. One particle leaves. No, no, in this case, two particles enter. No particles leave. Oh, that's a real good fight. That's a brother. That's a real good fight. Yeah. An antimatter particle out.
In the wilderness, can you identify it as such, unless you then see it annihilate? You can, yeah. And actually, the way it was discovered originally was by Karl Anderson, American physicist back in 1932. So he had this thing called a cloud chamber, which is this amazing instrument.
that allows you to see individual subatomic particles by they basically create these trails of water droplets as they go through the chamber which you can see as little traces. And he had one of these chambers at Caltech in California and he was seeing cosmic rays coming from
up outer space, and you see electrons, you see protons, and he had magnetic field on his chamber, and he saw one track that looked just like an electron. It had the same kind of form, but it was bending the wrong direction. So it was an electron with positive charge, and that was that one photograph was enough for Anderson to say, I've discovered antimatter. But I mean, now at CERN, there's a really cool experiment called alpha, where they actually
make atoms of anti matters they make anti hydrogen and they trap it in a magnetic bottle so you can't obviously keep it in a bottle because of denial at the bottle. If you have a really strong medic field you can store these things and keep them stored for hours now and then you can shine light on them and look at spectroscopy and all kinds of really cool stuff so we can actually kind of effectively store this stuff in very small quantities now.
So anti-hydrogen would be an anti-proton with an anti-electron in orbit around it. Yeah, if you get a chance to go to CERN, you should visit the alpha experiment because it's awesome. And just in all, in all, in the interest of disclosure regarding Carl Anderson, the existence of antimatter had just been predicted. Okay. Right. That was Fermi, correct? Dirac, Dirac. Dirac, Dirac, thank you. There was some
framework to even be able to interpret that result. Right. And so, and there was, yeah, Electron doing the opposite, opposite for its charge. Right. And, but otherwise, I'd add a little Electron. Same mass, same everything. That's pretty cool. Yeah, that was very cool. Yeah, very cool. Who knew I had a twin? Oh, an evil twin. An evil twin. Why does that twin have a goatee? That Electron has a goatee. What's going on?
That's the comic strip, the antimatter comic strip that we need. All right, but listen, Harry, thank you for being on StarTalk. We love what you do and we love how you talk about it. And now that you're in arms reach, I'd love to come back to you when we have particle physics questions.
Yeah, I'd be happy to. It's great talking to you. Really good fun. Do you have a presence on the internet? Do you have a handle that people can track you down? I do, yeah. You can find me at my website, harrycliff.co.uk if you want to see what I'm up to. I'm also on Twitter or X or whatever we're calling it, at harryvcliff. And your latest book, The Mysterious Anomalies Space Audities. The Mysterious Anomalies challenging our understanding of the universe. Nice. And there aren't many books about what we don't know. And this is just that kind of book. The things that are
That's hard what's that you know what I could write that book. You can write a whole book on what I don't know. I'm telling you right now. But you know scientists love things we don't understand that's that's how science makes progress and that's what the books about is about all these like weird little effects that could be nothing or they could be the clue to something really big and we're sort of trying to figure that out.
Yeah, we're looking forward to at Penguin Random House. Whoa, this year. Big time, buddy. Big time. All right. So we good here. So again, Harry, thanks for joining us. Chuck, are we good to have you, man? Always a pleasure. There's been yet another installment of Star Talk, cosmic queries, particle physics edition. Until next time, Neil, the grass ticing here bidding you to keep looking up.
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